A particular problem to which the present invention is addressed is the need for automatically counting the number of passengers which enter or exit a motor bus with accuracy. Prior systems which attempt to accomplish this task employ stair tread switches on two successive stair threads at the bus entrance passages for detecting the entrance or exit of passengers. The direction of passenger movement is determined by the sequence of occupancy of the stair treads. During heavy, close, passenger movement, the prior systems are inaccurate because the two stair tread signals do not provide sufficient information for accurate determination of the direction of travel of closely spaced occupants of the stair treads.
A prior system of the above type is presently marketed by the Dynamic Controls Corporation of South Windsor, Conn. as an "Automatic Passenger Counter System." That system is intended to accumulate data for a common carrier vehicle on the number of passengers boarding and departing from the vehicle at each stop, the number of passengers on board at any time, the total number of passengers carried on each trip, the real time and elapsed time for each stop, and the distance from the start of the trip to each stop. From that data, computations can be made of the average weekly passenger miles, the average weekly passenger trips, the average trip distance, and the average trip time. The present invention is directed to similar purposes, but to the accomplishment of those purposes with greater accuracy.
Accordingly, it is one object of the invention to provide an improved automatic counting system which provides improved reliability and accuracy in counting the number of bodies traversing a passage such as the entrance of a bus.
Another problem with the prior system has been that the stair tread switches are vulnerable to damage and wear.
Accordingly, it is another object of the invention to provide an improved automatic counting system for bodies traversing a passage which is much more reliable and has lower maintenance cost and lower vulnerability to wear and damage.